Pet Gazette March 2019 - Page 23

RVC | PET GAZETTE | 23 DIALYSIS DEVELOPMENTS FOR PETS By Simon Cook, lecturer in emergency and critical care at the Royal Veterinary College T he word dialysis will for many people conjure up images of human patients with chronic kidney failure hooked up to dialysis machines several times a week until they are able to receive a kidney transplant. At RVC Small Animal referrals we have the technology and expertise that allows us to help our patients in a much broader variety of circumstances. Our dialysis programme, which started in 2011, pushes the boundaries of veterinary medicine to enable us to offer the most effective treatment to our patients. Fundamentally, dialysis means the removal of waste products and fluids from the body, but the dialysis machine we have can be used in several different ways, including the following: Removal of waste products (including potassium) and fluid that accumulates when the kidneys suddenly stop working, for any reason. These are patients with acute kidney injury (AKI). This process would typically be performed two or three times over the course of a week, giving the injured kidneys time to heal of their own accord. This is called haemodialysis. Removal of toxins or overdosed drugs that are small molecules (e.g. ethanol, phenobarbital). This is also a form of haemodialysis but may only need to be performed once. Removal of part of the patient’s plasma. This can be beneficial in patients with immune-mediated disease or in those with toxins or overdosed drugs that are large molecules or highly protein bound (e.g. non-steroidal anti-inflammatory drugs). This would be termed therapeutic plasma exchange (or plasmapheresis). It involves removal of larger molecules, proteins including immunoglobulins, cytokines and fluid, while being replaced with donor plasma from our in-house blood transfusion service. Each of these three scenarios are slightly different to dialysis that is typically offered to human patients with chronic kidney disease. Dialysis for chronic kidney disease has been performed for dogs and cats in other countries but is a life-long treatment which we are not currently able to offer at the RVC. The main indication for dialysis at the RVC is therefore AKI. There are a number of different toxins that we are able to remove with dialysis. However, one of the common toxicities we see that causes kidney failure is ethylene glycol or antifreeze poisoning. To be effective with dialysis to treat ethylene glycol toxicity, we need to start dialysis within a very narrow time window (